BIOTIC

BIOTIC Species Information for Clavelina lepadiformis

Researched by

Karen Riley

Data supplied by

MarLIN

Refereed by

Dr Xavier Turon

Reproduction/Life History

Permanent hermaphrodite
Budding

Ovoviviparous
Lecithotrophic

Reproductive Season

June to September

Reproductive Location

As adult

Annual protracted

Life span

1-2 years

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

ca 50-60 embryos

Egg/propagule size

Fertilization type

Internal

Larvae/Juveniles
Larval/Juvenile dispersal potential	100-1000m	Larval settlement period	Late summer
Duration of larval stage	2-10 days

Reproduction Preferences Additional Information

Sea squirts are permanent hermaphrodites that undergo both sexual and asexual reproduction.

Sexual Reproduction:

Fish & Fish (1996) state that it is not easy to determine the age of ascidians, particularly that of colonial forms but that the lifetime is probably around one or two years. Each zooid reproduces sexually once, with the production of eggs possibly going on for weeks or months (Berrill, 1975). Breeding tends occur during June to September in temperate and cold seas (Picton, 1997; Millar, 1970), but in tropical waters it may continue throughout the year (Millar, 1970). In the Mediterranean, the breeding season is winter/spring (X. Turon, pers. comm.).
Fertilisation takes place internally, in the atrium, where development into the tadpole larvae stage also takes place (Fish & Fish, 1996; Berrill, 1950). This process is most likely to occur by cross-fertilization. Brunetti (1987) recorded up to about 50 embryos present in the atrium at one time whereas Tarjuelo & Turon (2004) gave an estimate of 66 embryos.
Clavelina lepadiformis brood a large number of small undifferentiated larvae (Tarjuelo & Turon, 2004).
After release, the larvae are free-swimming for about three hours (Fish & Fish, 1996; Brunetti, 1987). After this time the larvae settle on suitable substratum and metamorphosis into an adult sea squirt takes place. Development of the oozoid takes up to 3 days, and after 2-3 months of post-developmental growth they become sexually mature (Berrill, 1950).

Asexual reproduction:

Clavelina lepadiformis undergoes stolonic asexual budding. At the end of the sexual breeding season, towards the end of the summer, zooids disappear or are resorbed. Over the winter period the colony survives as 'winter buds' from which new zooids develop in spring (Berrill, 1950; Fish & Fish, 1996; Picton, 1997). In the winter months, when the zooids undergo de-differentiation, the resulting cylindrical bodies of many species of Clavelinidae are often found on rocky shores (Millar, 1970). In the Mediterranean the species reproduces in winter/spring and aestivates (aestivation is a period of inactivity / reduced metabolic activity) in summer (X. Turon, pers. comm.).

Reproduction References